Patterning germanene into superlattices: An efficient method for tuning conducting properties

Abstract

Using first-principles calculations, we have investigated electronic properties of germanene superlattices. Though bandgap can be obtained in all the superlattices by sublattice equivalence breaking, it could only be opened in some inversion symmetry preserved superlattices with Γ as four-fold degenerate Dirac point. The D6h antidot, though it does not harm the inversion symmetry, can still open bandgap by perturbing the four-fold degeneracy. Furthermore, the bandgap opened by either the sublattice equivalence breaking or the four-fold degeneracy perturbation could be continuously narrowed through reducing the defect density in germanene. These results are interesting to call for further theoretical and experimental studies.